Drill



J. D. NIXON March 28, 1933.

DRILL Filed June 29/1298}. Z Sheets-Sheet 1 March 28, 1933.

J. D. NIXON DRILL Filed Jun 29, 1931 2 Sheets-Sheet 2 Patented Mar. 28, 1933 UNITED ST TES JE DDY D. NIXON, OF HOUSTON, TEXAS DRILL Application filed June '29,

This invention relates to a drill.

An object of the invention is to provide a drill having a head and detachable cutters secured thereto in a novel manner.

Another object of the invention is to provide a drill embodying a head and detachable cutters mounted therein with means whereby the cutters will be at all times clamped in immovable relation to the head.

Another object is to provide, in a drill, means for automatically taking up the slack, or movement, of the drill cutters relative to the head.

Another object of the invention is to provide, in a drill, a novel type of blade.

A still further object is to provide, in a drill, a blade having a novel type of hard surface cutting edge thereon.

With the above and other obi'ects in view this invention has particular re ation to certain novel features of construction, operation and arrangement of parts an example of which is given in this specification and illustrated in the accompanying drawings,

wherein:

Figure 1 shows a vertical sectional v1ew of the drill taken on the line 11 of Figure 4.

Figure 2 shows a fragmentary side elevation.

Figure 3 shows a transverse sectional view taken on the line 33 of Figure 2.

Figure 4 shows a bottom end view.

Figure 5. shows an upper end view of a cutter blade employed. I

Figure 6 shows a front elevation of said blade, partly broken away.

Figure 7 shows an edge view, and

Figure 8 shows a sectional view taken on the line 8-8 of Figure 6.

Referring now more particularly to the drawings, wherein like numerals of reference designate similar parts in each of the figures, the numeral 1 designates the drill head which may be of a cylindrical form. The upper end of the head may have a tapering, internally threaded box 2 to receive the pin 3 of the drill collar 4 by means of which the drill may be attached to the drill stem.

1931. Serial 170.347309.

The lower end of the head has an axial bore 5 whose upper end is reduced and internally .threaded as at 6. The upper end of this bore terminates beneath the lower end ofthe box 2. L

There are the vertical slots 7 which radiate from the enlarged portion of the bore 5 and which are spaced apart around the head. These slots, as shown, taper upwardly.

There are suitable cutters, as shown, said cutters being in the-form of blades 8. These cutters have their upper ends fitted into the slots 7, said ends bem tapered to wedge in said slots. The bla es preferably extend out laterally beyond the head. The inner margins of the blades have the widened arcuate tenons 9, and said tenons conform to the shape of, and fit against, the wall of the bore 5.

There is a center drill 10 which fits closely within the lower ends of the blades 8 and which has a reduced, upwardly extending shaft 11, preferably integral therewith.

The upper end of the drill 10 abuts the lower ends of the tenons 9 and the shaft 11 fits closely within said tenons and its upper end is threaded and screwed up into the threaded upper end of the bore 5, the upper end of said shaft being spaced from the opposing .upper end of said bore.

The lower end of 'the blades 8 may be forwardly curved, as shown, if desired, and the center drill may also have forwardly curved blades 12. It is to be understood that the drill cutters may be made of any selected design .and may be provided with cuttin edges, or may ing members thereon.

When the drill is assembled, the upper ends of the blades will be spaced beneath have rolling cutters, or abra the upper ends of the slots 7 as shown, and

strain on the center drill 10 will cause the shaft 11 to screw further up into the threaded portion of the socket 5, with the result that the blades will be wedged further up into said slots and the-wear, and play of the blades taken u and the blades thus maintained immova ly anchored in place.

The head may have the water courses 13 leading downwardly therethrough from the box 2 to the lower end of the head and terminating in front of the blades 8 through which a flushing fluid may be supplied to bottom of the bore to carry away the cuttin s.

11 Figures 6, 7 and 8 there is shown a special type of blade which is hardsurfaced in a novel manner. Adjacent the side and bottom cutting edges of the blade the front side, or face, of the blade is provided with grooves 14, said grooves preferably extending diagonally and terminating at said edges.

A suitable hard surfacin material 15 is then run onto said grooved face, said material filling said rooves 14, as shown in Figure 8, thus forming the ribs 16 on the underside of the hard surfacing material, in said grooves. As-the blades wear away the material of the blades and the hard surfaclng material between said ribs will wear faster than the ribs themselves and said cutting edges will gradually assume. a serrated contour forming teeth which will maintain the gauge of the bore and be very effective in abrading away the material at the bottom of the bore.

The drawings and description disclose what is now considered to be a preferred form of the invention, by way of illustration only while the broad principle of the invention will be defined by the appended claims.

What I claim is: 1. A drill including a head, detachable blades therein said head having downwardly flared slots and said blades having upwardly tapered portions in said slots, arcu-- ate tenons on the inner margins .of the blades, a center drill engageable against the lower ends of said tenons and having a shaft fitted between, and surrounded by the tenons which has a threaded connection with said head, said center drill being .turnable, relative to the head during drilling o era-' tions, to exert a pressure against said lade tenons.

'2. A drill including ahead having an axial bore in its lower end and slots radiating from the bore, blades in said slots whose inner margins have arcuate tenons in said I bore, a center drill abutting the lower ends of the tenons and having a shaft which is fitted between and surrounded by the tenons and has a threaded connection with the head, said threaded connection bein formed to permit said shaft-to be screwe further cutting means 3. A drill including a head having an axial bore in its lower end and upwardly tapered slots radiating from sa1d bore, blades fitted into said slots having mar inal abutments which engage the walls 0 the bore, a center drill whose upper end engages said abutments, a shaft on said center drill which fits between said abutments and has a threaded connection with the head, said connection being formed to permit the shaft to turn relative to the head during drilling operations. I

4. A drill for forming a bore including a cutter support having upwardly tapered side slots, detachable cutters thereon having tapered portions in said slots, means having a threaded connection with the drill and engaging the cutters and shaped to engage the material at the bottom of the bore whereby said means may be caused to rotate and to 5. An earth boring drill including a cutter support whoselower end is formed with a bore having side slots and having its upper end internally threaded, cutting means having a vertical bearing in said here, said extending out laterally through said slots, said cutting means having a downwardly facing abutment, a center drill having an upwardly extended shank which fits through said bearing and whose upper end is threaded into the threaded portion of said bore, said center drill engaging sa1d abutment, said center drill, be-

ing shaped to engage the material at the.

bottom of the bore being drilled whereby said center drill ma be caused to rotate and to move upward relative to the support, upon rotation o the drill in the bore, to take up the wear of said cutting means,

whereby the cutting means will be maintained tightly clamped in said slots.

In testimony whereof I have signed my name to this specification.

JEDDY D. NIXON. 

